Repair techniques for micro LED devices and arrays

Abstract

Repair techniques for micro LED devices and arrays are disclosed. Various repair technique embodiments according to the structures and methods are provided to overcome and mitigate defective pixels, and improve yield and reduce costs of the emissive display system.

Description

[0001] Information about divisional applications

[0002] This case is a divisional application of the invention patent application with the application date of April 8, 2020, application number 202080027485.7, and invention name "Repair Technology for Micro LED Devices and Arrays".

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62 / 831,403, filed on April 9, 2019, and U.S. Provisional Patent Application No. 62 / 831,564, filed on April 9, 2019, each of which is incorporated herein by reference in its entirety. Technical Field

[0005] The present disclosure generally relates to micro LED displays, and more particularly, provides repair techniques for micro LED displays. In addition, the present disclosure also relates to optoelectronic solid-state array devices, and more particularly to methods and structures for improving light output distribution of solid-state array devices. Background Art

[0006] Testing and repairing micro-LED displays including micro-devices transferred onto system substrates is critical to improving yields. Summary of the invention

[0007] Although using spare microdevices can improve yield, it also increases cost. The embodiments described below are intended to achieve a simple and / or practical repair process to improve yield and reduce cost.

[0008] According to one embodiment, a display system on a system substrate may be provided. The display system may include a pixel array, wherein each pixel includes a group of sub-pixels arranged in a matrix; the group of sub-pixels includes at least one defective sub-pixel; and a defect mapping block for mapping data from the at least one defective sub-pixel to at least one surrounding spare sub-pixel.

[0009] According to another embodiment, a method for repairing a pixel circuit comprising multiple pixels may include: providing a group of more than two sub-pixels and a spare sub-pixel for each pixel; detecting at least one defective sub-pixel in the group of sub-pixels; and converting the spare sub-pixel using color conversion or a color filter to produce the same color as the defective sub-pixel.

[0010] In another embodiment, a method of repairing a pixel circuit may be provided. The method may include: providing a pixel including more than one primary sub-pixel having high wavelength emission; applying a color conversion material to at least one of the primary sub-pixels to convert the high wavelength emission to an emission wavelength different from the high wavelength emission; identifying a defective sub-pixel in the primary sub-pixel; and mapping a spare sub-pixel to the same primary color as the defective primary sub-pixel by using the color conversion material.

[0011] According to yet another embodiment, a method of repairing a pixel circuit may be provided. The method may include: providing a pixel including more than one primary sub-pixel having a combined wavelength emission; applying a color filter material to at least one of the primary sub-pixels to convert the combined wavelength emission to a different emission wavelength; identifying a defective sub-pixel in the primary sub-pixel; and mapping a spare sub-pixel to the same primary color as the defective sub-pixel using the color filter material.

[0012] According to some embodiments, a method for repairing a pixel circuit may be provided. The method may include: providing a pixel including at least one high wavelength main sub-pixel; providing at least one spare sub-pixel having the same wavelength; identifying defective sub-pixels in the main sub-pixels and the spare sub-pixels; and mapping a color conversion layer to sub-pixels without defects so that there is at least one sub-pixel for each expected main sub-pixel.

[0013] According to another embodiment, a method for repairing a pixel circuit may be provided. The method may include: providing a pixel including at least one combined color sub-pixel; providing at least one spare sub-pixel having the same combined color; identifying defective sub-pixels in the primary pixel and the spare sub-pixels; and mapping the color filter layer to the non-defective sub-pixels so that there is at least one sub-pixel for each expected primary sub-pixel.

[0014] According to another embodiment, a method for replacing a defective sub-pixel with a spare sub-pixel in a display system may include: providing periodic spatial changes to the positions of sub-pixels in a display; calculating the maximum distance and the minimum distance between the spare sub-pixel and the defective sub-pixel; extracting the coordinate changes of the sub-pixel; and replacing the defective microdevice with the spare sub-pixel based on the calculated changes.

[0015] According to yet another embodiment, a method of correcting spatial non-uniformity of an array of optoelectronic devices is performed by blocking a portion of a signal generated or absorbed by an optoelectronic device based on the spatial non-uniformity in the array.

[0016] The present invention also relates to methods and structures for improving light output distribution of solid-state array devices.

[0017] According to one embodiment, a method of manufacturing a pixelated structure may be provided. The method may include: providing a donor substrate including a plurality of pixelated micro-devices; bonding a selected set of pixelated micro-devices from the donor substrate to a system substrate; and patterning a bottom conductive layer of the pixelated micro-devices after separating the donor substrate from the system substrate.

[0018] According to one embodiment, a donor substrate having a plurality of micro devices may be provided, wherein a bonding filler and a filling layer fill spaces between the micro devices.

[0019] According to another embodiment, the donor substrate may be removed from the lateral functional device.

[0020] According to one embodiment, one or more bottom layers of the donor substrate (or donor substrate) after separation may be patterned.

[0021] According to some embodiments, patterning can be done by completely isolating the layers or leaving some thin layers between the patterns.

[0022] According to other embodiments, specific ohmic contacts may be required to properly connect to the patterned bottom conductive layer.

[0023] According to one embodiment, the ohmic contact may be one of an opaque or transparent material.

[0024] The foregoing summary is illustrative only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The foregoing and additional aspects and embodiments of the present disclosure will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments and / or aspects with reference to the accompanying drawings, a brief description of which is provided below.

[0026] FIG. 1( a ) illustrates an example of a pixel array that does not include a defective sub-pixel.

[0027] FIG. 1( b ) illustrates an example of a pixel array including transferring defective sub-pixel contributions to spare sub-pixels.

[0028] FIG. 2( a ) shows an example of a pixel array having one spare sub-pixel for each pixel.

[0029] FIG. 2( b ) shows an example of a pixel array including transferring a defective sub-pixel contribution to a spare adjacent sub-pixel.

[0030] Figures 3(a) to 3(c)A predefined mapping technique for repairing defective microdevices is demonstrated.

[0031] Figures 4(a) to 4(c) A proximity mapping technique for repairing defective microdevices is demonstrated.

[0032] Figures 5(a) to 5(c) A surround mapping technique for repairing defective microdevices is demonstrated.

[0033] Figure 6 A weighted mapping technique for repairing defective microdevices is demonstrated.

[0034] FIG. 7( a ) shows a two-dimensional distribution of spare elements distributed over rows and columns of a pixel array.

[0035] FIG. 7( b ) shows a one-dimensional distribution of spare elements distributed across rows and columns of a pixel array.

[0036] FIG7(c) shows a one-dimensional distribution of spare elements distributed on the same row or adjacent rows where a defect is detected.

[0037] FIG. 8A(a) shows an example of a pixel array with fixed RGB and spare blue sub-pixels, where a defective green sub-pixel is detected during post-production inspection.

[0038] FIG. 8A( b ) shows an example of a pixel array with fixed RGB and a spare blue subpixel, where the spare blue subpixel is switched to green.

[0039] FIG8B(a) shows an example of a pixel array with fixed RGB and alternate combined color sub-pixels, where a defective green sub-pixel is detected during post-production inspection.

[0040] FIG. 8B(b) shows an example of a pixel array in which the alternate combined color sub-pixel is switched to green.

[0041] Figures 9(a) to 9(c) The architecture of a pixel array populated by blue microdevices is shown.

[0042] FIG. 10( a ) shows the periodic spatial variation of the position of a microdevice in a display system.

[0043] FIG. 10( b ) shows the random spatial variation of the position of a microdevice in a display system.

[0044] FIG. 10( c ) shows an example of transferring different microdevices from a source to a system substrate.

[0045] FIG10( d ) shows a system substrate with a landing area corresponding to the variation of the source microdevice.

[0046] Fig.11 A sequence of steps for spatial variation of the position of a microdevice in a display system is presented.

[0047] Fig.12 Random spatial variations in the position of microdevices in a display system are shown.

[0048] Fig.13 A schematic diagram of a micro device arranged with a circuit according to an embodiment of the present invention is shown.

[0049] Fig.14 A sequence of steps for remapping sub-pixels according to an embodiment of the present invention is shown.

[0050] Fig.15 A sequence of steps for remapping sub-pixels according to another embodiment of the present invention is shown.

[0051] Fig.16 A schematic diagram of a micro device arranged with a circuit according to another embodiment of the present invention is shown.

[0052] Fig.17 A schematic diagram of a micro device arranged with a circuit according to another embodiment of the present invention is shown.

[0053] Fig.18 A schematic diagram of a micro device arranged with a circuit according to another embodiment of the present invention is shown.

[0054] Fig.19 A schematic diagram of a micro device arranged with a circuit according to another embodiment of the present invention is shown.

[0055] Fig. 20A A cross-sectional view of a lateral functional structure on a donor substrate according to an embodiment of the present invention is depicted.

[0056] Fig. 20B A cross-sectional view of the lateral structure of FIG. 1( a ) is depicted with a current distribution layer deposited thereon, in accordance with an embodiment of the present invention.

[0057] Fig. 20C A cross-sectional view of the lateral structure of FIG. 1( b ) is depicted after patterning the dielectric, top conductive layers, and depositing a second dielectric layer in accordance with an embodiment of the present invention.

[0058] Fig.20D A cross-sectional view of the lateral structure after patterning the second dielectric layer is depicted according to an embodiment of the present invention.

[0059] Fig.20E Depicted is a cross-sectional view of a lateral structure after deposition and patterning of a filler according to an embodiment of the present invention.

[0060] Fig.20F A cross-sectional view of a lateral structure after bonding to a system substrate is depicted, wherein the bonding area forms an integrated structure in accordance with an embodiment of the present invention.

[0061] Figure 20G A cross-sectional view of the integrated structure after removal of the donor substrate and thinning of the bottom electrode is depicted in accordance with an embodiment of the present invention.

[0062] Fig. 20H A cross-sectional view of the integrated structure after removal of the donor substrate and the patterned bottom electrode is depicted in accordance with an embodiment of the present invention.

[0063] Fig.21A A cross-sectional view of an integrated structure is shown in accordance with an embodiment of the present invention, wherein the patterned bottom electrode has an ohmic contact.

[0064] Figure 21B-1 A cross-sectional view of an integrated structure is shown in accordance with an embodiment of the present invention, wherein the ohmic contacts are inside the isolated patterns of the patterned bottom electrode.

[0065] Figure 21B-2 A cross-sectional view of an integrated structure according to an embodiment of the present invention is shown, wherein the ohmic contacts are at the edges of the isolated patterns of the patterned bottom electrode.

[0066] Fig. 21C A cross-sectional view of an integrated structure covering a patterned bottom electrode with a common electrode according to an embodiment of the present invention is shown.

[0067] Although the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown in the drawings by way of example and will be described in detail herein. However, it should be understood that the present disclosure is not intended to be limited to the specific forms disclosed. On the contrary, the present disclosure will cover all modifications, equivalents and alternatives within the spirit and scope of the present invention defined by the appended claims. DETAILED DESCRIPTION

[0068] There are several sources of defects that can occur in micro-LED displays, including device (micro-LED) open / short issues, device transfer / integration / bonding defects, and substrate driver pixel defects. Repairing micro-LED displays that include defective micro-devices that transfer to the system substrate is critical to improving yield. While using spare micro-devices can improve yield, it also increases cost. The following embodiments are intended to enable repair techniques to improve the yield and reduce the cost of emissive displays.

[0069] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0070] As used in the specification and claims, the singular form "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0071] In this specification, the terms "device" and "microdevice" are used interchangeably. However, it will be clear to those skilled in the art that the embodiments described herein are independent of device size.

[0072] In this specification, the terms "donor substrate" and "microdevice substrate" are used interchangeably.

[0073] In this specification, the terms "receptor substrate" and "system substrate" are used interchangeably.

[0074] Examples of optoelectronic devices include sensors and light emitting devices, such as light emitting diodes (LEDs).

[0075] As used herein, the term "comprising" will be understood to mean that the following list is not exhaustive and may or may not include any other suitable items, such as one or more suitable other features, components and / or elements.

[0076] Defect repair technology

[0077] In microdevice system integration, the device is manufactured under its natural environment conditions and then transferred to a larger system substrate. In one case, the microdevice is functional after being placed on the system substrate because the microdevice has a functional connection with the system substrate. In another case, post-processing is required to make the device functional. Common processing steps include establishing a connection between the microdevice and the system substrate. In this case, the system substrate can be planarized first and a thick (1 to 2 micron) dielectric layer is deposited on top of the system substrate. If necessary, the contact area with the microdevice is opened by patterning and etching the planarization layer. Thereafter, if necessary, the electrodes are deposited and patterned.

[0078] In this specification, the terms "device" and "microdevice" are used interchangeably.

[0079] However, it will be apparent to those skilled in the art that the embodiments described herein are independent of device size.

[0080] In this specification, the terms "backup device" and "redundant device" are used interchangeably. However, it is clear to those skilled in the art that "backup device" and "redundant device" are similar in meaning to devices that are not absolutely necessary for the function but are included in the event of a failure of another device.

[0081] The main challenge of this integration is to identify defective transfer devices and repair them or emitter displays when necessary. After testing, defective pixels are identified. Defective pixels can be repaired or disabled. One way to repair defects after identification is to remove the defective device from the pixel and replace it with a new device. The main disadvantage of this is the risk of damaging the pixel when removing the defective device. Various repair technology embodiments based on the provided structure and process are described in detail below to overcome and mitigate defective pixels.

[0082] Redundancy schemes consisting of multiple redundancy, distributed redundancy, and defect mapping techniques are included. Other embodiments include repair by color conversion, including fixed sub-pixels with redundant blue structures and all blue structures.

[0083] Here, embodiments are described in the context of pixelated systems (e.g., displays, sensors, and other array structures), however, similar methods can be used for other system configurations. In addition, although the embodiments illustrate the technology applied to micro devices, it should be understood that they can be applied to any other device size.

[0084] In one method shown in FIG. 1( a), a pixel circuit 102a may include a plurality of pixels integrated on a system substrate (not shown in FIG. 1( a)) of a display system. Each pixel such as 104a, 106a, and 108a may include a group of sub-pixels, including a sub-pixel and a group of spare sub-pixels of the same primary color. Each sub-pixel array is configured to emit a separate primary color. For example, a first group of sub-pixels 104a may emit a red primary color, a second group of sub-pixels 106a may emit blue, and a third group of sub-pixels 108a may emit green. Each sub-pixel may be a micro-LED.

[0085] In such a system, when, for example, one of the sub-pixels is detected to be defective after the integration process, the brightness contribution of the defective sub-pixel 110b can be transferred to the spare sub-pixel 104b, as shown in Figure 1(b). Each spare sub-pixel of each pixel can be configured to emit the same primary color as the defective sub-pixel.

[0086] In such Figure 2(a) and 2(b)In another embodiment shown, where it is desired to limit the number of integrated microdevices, sparse redundancy of the pattern shown in FIG. 2( a) may be utilized. In the system of FIG. 2( a), pixel clusters (4 full pixels) may be integrated on a substrate (not shown in FIG. 2( a)), where each cluster 202a may include a set of pixels and a set of spare subpixels, and each pixel includes a set of subpixels (R, G, B) and a spare subpixel, such as 204a and 206a. In such a system, when subpixel 202b is detected to be defective after the integration process, the brightness contribution of the defective subpixel may be transferred to the spare subpixel 204b, as shown in FIG. 2( b).

[0087] In the above methods and embodiments, since the configuration has four micro-LEDs for each sub-pixel and one of the micro-LEDs is non-functional, the brightness of each of the remaining micro-LEDs will be increased by 1 / 3 to compensate for the brightness loss caused by the defective micro-LED. The main problem with these methods is that the number of micro-LEDs per display increases dramatically. Therefore, the cost of materials also increases. Therefore, for some defect repair mechanisms where the display controller needs to redirect the data flow to redundant circuits, defect mapping techniques are used. These techniques rely on using two or more redundant elements to artificially move the effective coordinates of the repair elements within the constructed image.

[0088] Figures 3(a) to 3(c) A predefined mapping technique for repairing defective micro devices is presented. In one embodiment, a display system having a pixel array and having at least one defective pixel in the pixel array can utilize a predefined set of redundant elements. In this case, each defective micro device is mapped to one or more spare micro devices near the defective device. Functions (e.g., brightness) are shared between mapped spare devices with predefined values. Therefore, the brightness value of the defective sub-pixel is shared between the surrounding spare sub-pixels based on the predefined value. For example, as shown in 302b, the green defective sub-pixel 304b can be mapped to two adjacent spatial green micro LEDs 306b and 308b. Each of the spare micro LEDs 306b and 308b can produce 50% of the brightness of the defective green sub-pixel 304b. An example of this is shown in FIG. 3(b). Similar methods can also be used for red and blue defective sub-pixels, as shown in 302a and 302c.

[0089] In other embodiments, the brightness share of the spare device is calculated based on the geometric distance between the defective pixel and the surrounding spare devices. A lookup table or formula can be used to extract the brightness share of the surrounding spare devices. In one example, Figures 4(a) to 4(c)As shown in FIG. 4( a ), a display system 402a having a pixel array and at least one defective pixel 406a in the pixel array can utilize a spare device 404a based on the shortest geometric distance between the defective pixel and the spare device. Figure 4(b) and 4(c) A similar method may be used for defective green and blue sub-pixels, as shown in display systems 402b and 402c, respectively.

[0090] In another example, surround mapping techniques can be used to repair defective microdevices, such as Figures 5(a) to 5(c) As shown. In one embodiment, a display system 502a including multiple sub-pixels and at least one defective pixel can equally utilize adjacent or surrounding spare devices. The brightness (or signal) of the defective device is equally replaced by adjacent devices. If there are three spare devices around the defective device, 1 / 3 of the brightness (or signal) is generated by each spare device. In one example, as shown in FIG5(b), three spare devices (504b, 506b, and 508b) surround a defective green device 510b, and 1 / 3 of the brightness (or signal) is generated by each spare device. The brightness (or signal) of the defective green device 510b is equally replaced by adjacent spare green devices (504b, 506b, and 508b). As Figure 5(a) and 5(c) A similar method may be used for defective green and blue sub-pixels, as shown in display systems 502a and 502c, respectively.

[0091] Figure 6 A weighted mapping technique for repairing a defective micro-device is presented. In one embodiment, a display system 600 including a plurality of spare sub-pixels and at least one defective pixel 602 can utilize an accurate ratio of geometric distances to the defective sub-pixel. A brightness share of each spare sub-pixel (604, 606, 608, and 610) is calculated based on the accurate ratio of geometric distances to the defective sub-pixel 602.

[0092] In another embodiment, any combination of the above embodiments is also feasible. The brightness in the above embodiments can be any other signal output from different micro devices.

[0093] There are many other methods that can be used to repair defective micro devices. In one method, in a display system 702a having a pixel array, a two-dimensional distribution of redundant elements distributed on rows and columns of the pixel array can be used, as shown in Figure 7(a). In another method, in a display system 702b having a pixel array, a one-dimensional distribution of redundant elements distributed on rows and columns of the pixel array can be used, as shown in Figure 7(b). In yet another method, in a display system 702c having a pixel array, a one-dimensional distribution of redundant elements distributed on the same or adjacent rows where a defect is detected can be used, as shown in Figure 7(c).

[0094] In yet another case, a display system having a pixel array may utilize the above described situation and have a buffer memory having a size corresponding to the number of rows occupied by the distributed redundancy to store and reuse video / image data.

[0095] In another case, a display system having a pixel array can utilize the above situation and have a buffer memory sized to correspond to a single row (where a defective pixel is detected) to store and reuse video / image data.

[0096] Defect mapping can be implemented at different levels / layers of a display system. In one embodiment, a display system having one or more defective pixels / sub-pixels is repaired by physically mapping the defective pixels / sub-pixels to a single or a set of spare / redundant repair elements (e.g., post-manufacturing laser repair).

[0097] In one embodiment, a display system having one or more defective pixels / sub-pixels is repaired by driver mapping the defective pixels / sub-pixels to a single or a set of spare / redundant repair elements (i.e., programmable flash, OTP memory, or fuses in a driver component).

[0098] In yet another embodiment, a display system having one or more defective pixels / sub-pixels therein is repaired by soft mapping (i.e., mapping by a timing controller (TCON)) of the defective pixels / sub-pixels to a single or a group of spare / redundant repair elements. In another embodiment, a display system having one or more defective pixels / sub-pixels therein is repaired by any combination of the above embodiments.

[0099] Repair by color conversion

[0100] In most cases, defective pixels can only be detected after the display system common electrode is deposited. Therefore, physical repair of defective elements may become challenging. Disclosed are various embodiments illustrating several design methods and manufacturing techniques to facilitate the repair process.

[0101] Fixed sub-pixel with redundant blue structure

[0102] 8A shows a pixel array with fixed RGB and redundant blue sub-pixels. In this embodiment 802a, each pixel may contain a fixed combination of sub-pixel elements (RBG, RGBW, or other combinations of stripes, diamonds, or other patterns). Each pixel may further include additional blue or combination colors (e.g., white, orange, yellow, purple) sub-pixels (804a, 806a) that can be used for repair purposes.

[0103] Once the integration, passivation and common electrode deposition steps are completed, the display panel can be inspected to detect and record the coordinates of the defective pixels. Post-processing equipment on the production line can then cover (print, pattern or stamp) the redundant blue sub-pixel with a color conversion material (quantum dots or phosphors) to replace the defective sub-pixel or in the case of a combined color device, a color filter can be used to extract the desired color of the defective sub-pixel.

[0104] A 2x2 array 802a of such a system using an RGB subpixel assembly and a spare blue subpixel is depicted in FIG8A(a) and FIG8A(b). Once a subpixel in the array is detected to be defective, the spare blue can be converted to the same primary color as the defective subpixel using a color conversion material (FIG8A(b)). For example, a fixed RGB and spare blue subpixel (804a, 804b) can be provided in pixel 808a. During post-production inspection, if a defective green subpixel 810a is detected, the spare blue subpixel can be converted to green 812a using a color conversion material.

[0105] FIG8B(a) and FIG8B(b) show a pixel array 802b where the redundant white sub-pixel is converted to green. In the case of the combined colors shown in FIG8B , the spare device will be covered by a color filter to produce the same primary color as the defective sub-pixel ( Figure 8B(a) and 8B(b) ). For example, the RGB and spare white sub-pixels (804b, 806b) may be fixed in pixel 808b. During post-production inspection, if a defective green sub-pixel 810b is detected, the spare blue sub-pixel may be converted to green 812b using a color conversion material. Blue or white are used as examples and may be replaced with other high energy photons or combination colors.

[0106] All blue or combination color structure

[0107] Figures 9(a) to 9(c)The architecture of a pixel array filled with blue microdevices is shown. As shown in FIG. 9( a), the entire array 902 can be filled with only one type of high-wavelength main microdevice (e.g., blue or a combination of colors). The display system shown in FIG. 9( a) has an all-blue micro-LED array. Subsequently, the filled array may undergo multiple post-integration processes, such as passivation, planarization, and common electrode deposition. The inspection system can then determine the coordinates of the defective pixels. As shown in FIG. 9( b) to (c), the display panel may then undergo production steps in which the functional sub-pixels may be covered (printed, patterned, or stamped) by color conversion (quantum dots or phosphors) or color filter materials to form the desired color pixel pattern (RGB, RGBW, RGBY, etc.) using a fixed or spatially optimized mapping. In the same production step, all defective pixels will be remapped by color conversion of the redundant blue sub-pixels. For example, as shown in FIG. 9( a), the array 902 can be filled with all blue sub-pixels. During post-production inspection, a defective green sub-pixel 910 is detected, and the spare blue sub-pixel can be converted to green 912 using a color conversion material. In one embodiment, in the case of a combined color device, a color filter may be used to extract the desired color of the defective sub-pixel.

[0108] Space coordinate changes

[0109] In most repair processes using redundant or spare micro devices, there is a difference in spatial coordinates between the actual defective device and the spare or redundant device. This can be seen as a visual artifact. To address this issue, one embodiment of the present invention adds predefined (or periodic) spatial coordinate changes to the device. The changes can be in one direction or in two directions. Here, the maximum distance and minimum distance between the spare device and the defective device that it may represent are extracted. Then, the changes in coordinates are extracted to minimize the impact of the spare device position.

[0110] Figure 10(a) shows periodic spatial variation of position microdevices 1002 in display system 1000a using RGB. Figure 10(b) shows another example where random spatial variation is added to microdevices 1002b (eg, R, G, B) in display system 1000b. Figure 10(a) and 10(b) The same method described in can be used for displays with different devices or systems with different functions. Here, the RGB device 1002a has a horizontal direction. However, they can have different directions. In addition, the spatial variation is applied to the RGB samples 1002b in the same order. However, each device can have a different spatial variation. In addition, the spare device 1004a is added to some of the space between the actual functional devices. The spare device 1004b can also have a spatial variation.

[0111] FIG10( c ) shows an example of transferring different microdevices from a source to a system substrate. In one approach, the method of generating spatial variations is to fabricate microdevices with induced spatial variations. Here, a system substrate 1000 c to which a microdevice 1002 c is to be transferred after fabrication of the microdevice has a similar variation in the landing area in the system substrate to which the microdevice is to be transferred.

[0112] FIG. 10( d ) shows a system substrate with a landing area array 1000 d corresponding to variations in microdevices from a source. In another approach, the transfer process accommodates such variations. Here, microdevices such as 1002 d are located in a two-dimensional array structure with a pitch that is less than the pitch of the two-dimensional landing area array 1000 d in the system substrate. The transfer method used herein is a process of transferring microdevices of different pitches from a microdevice source to a landing array. Here, the landing array can accommodate different microdevice pitches. The landing area is larger to accommodate such variations, or the landing areas have similar pitch variations.

[0113] In another embodiment, to further improve uniformity, the induced variation is limited to a permissible non-uniformity in the signal of the microdevice. The permissible spatial non-uniformity may be a global non-uniformity calculated based on the average microdevice signal in a region including at least one microdevice. The permissible spatial non-uniformity may be a local non-uniformity based on variations in the sensed signals of neighboring microdevices.

[0114] In yet another embodiment, in order to eliminate unwanted non-uniformities caused by variations in the coordination of the micro-devices, it may include calibrating the system for the induced variations. The calibration may include modifying the signals of the micro-devices according to the positions of the micro-devices.

[0115] The orientation and location of the microdevices in the pixels are used as exemplary arrangements and the methods described above may be used with different arrangements.

[0116] Fig.11 A flow chart 1100 is shown that includes steps for creating spatial variations and eliminating unwanted non-uniformities caused by the variations. Fig.11 The order of the steps shown may be changed without affecting system performance. Fig.11An example of steps is shown. A first step 1102 includes calculating a maximum allowable spatial variation based on an acceptable spatial non-uniformity in the signal of the microdevice. In step 1104, a number of spare microdevices can be calculated based on the defect rate of the microdevices and the allowable spatial non-uniformity and other parameters (e.g., cost). In step 1106, the microdevices can be transferred to the system substrate based on the calculated spatial variation, and in step 1108, the spare microdevices can be allocated among the microdevices in the system substrate based on the allowable variation and the defect rate. In step 1110, the defective microdevice is replaced with the spare microdevice. In step 1112, the system can be calibrated based on the induced variation and the spare microdevices, and in step 1114, the microdevice signal is corrected using the calibration data.

[0117] Fig.12 A correction method for at least a portion of different non-uniformities is shown, such as non-uniformities from spatial variations, non-uniformities from device processes, non-uniformities from system substrates, or non-uniformities from the integration process of the microdevice into the system substrate. Here, part of the signal generated or absorbed by the microdevice is blocked. The area (A1) 1202 that blocks the signal is proportional to the signal of the microdevice.

[0118] In one embodiment, the signal is created prior to transmission as part of the device process or integration process. If it is part of the device process, the performance of the microdevice or the layers prior to creating the microdevice are evaluated. After the evaluation, during the device process, an opaque material is used to block the signal, or region A1 of the device is modified to region (A2) 1204 to correct for the measured non-uniformity in performance.

[0119] In another embodiment, the blocking region 1204 is created after the device is transferred to the system substrate. In this case, the device performance is measured at different stages after or before the transfer. The data is then used to create an opaque layer that blocks the signal or adjusts the region A2 of the device to correct the measured performance non-uniformity.

[0120] In one embodiment, an opaque layer is deposited and patterned on top of the optoelectronic device, wherein the area of ​​the opaque layer is proportional to the spatial non-uniformity. The opaque layer can be part of the contact layer of the optoelectronic device. In another case, the opaque layer is part of the array electrode. In addition, the size of the optoelectronic device is modified according to the spatial non-uniformity.

[0121] In one embodiment, after identifying a group of defective micro devices, the type of micro devices in at least one pixel can be remapped based on the defective micro devices. For example, in a display pixel, the type of micro device can be one of red, blue or green micro LEDs. In this case, based on the defect in one micro LED, other micro LEDs can be mapped to different colors to reduce the impact of the defect. In one case, based on the remapped information, programming data is sent to the corresponding data line. For example, if in a pixel, the micro LED assigned to red is defective and the spare micro LED (or one of the other micro LEDs) is mapped to red, the red data will be redirected to the circuit assigned to the newly mapped red micro LED. Remapping can be achieved by sending data to the data line corresponding to the newly mapped micro LED. In another case, the connection between each micro device and the corresponding pixel circuit is rearranged based on the remapped information. In one embodiment, the micro device can be connected to the bonding area that connects the micro device to the backplane according to the mapping information after defect analysis. The bonding area may include bonding fillers / bumps or metallization through a through hole between the micro device plane and the backplane.

[0122] An optoelectronic system composed of micro devices includes an array of micro devices, an input unit for obtaining input data (such as video data), a data processing unit for processing the input or output data, a timing controller for synchronizing the addressing of the micro devices in the array with the input or output data, a driving unit for setting the data lines in the array using values ​​representing the input data, and an address driver for causing the micro devices in the array to perform different operation stages (such as programming, driving or calibration).

[0123] Fig.13 A schematic diagram of a micro device with pixel circuits arranged according to an embodiment of the present invention is shown. Here, a plurality of micro devices 1302 (MD1, MD2, MD3, MD4) can be connected to their corresponding pixel circuits 1304 and data lines 1306. In one case, the connection between the pixel circuit 1304, the data line (or other signal line) 1306 and the micro device 1302 is fixed. In this case, if the type of the micro device (e.g., red, green or blue) is rearranged, the programming data (or other signal) programmed to the data line 1306 of the pixel circuit 1304 needs to be redirected on the programming side of the data processing or timing controller or driving unit.

[0124] Fig.14A sequence of steps for remapping subpixels according to an embodiment of the present invention is shown. At step 1402, a group of defective microdevices or pixels can be identified from an array of microdevices. At the next step 1404, the type of microdevice can be remapped to reduce the impact of the defects. At the next step 1406, the remapped information (new subpixel arrangement) can be stored, and at step 1408, the programming side in the data processing or timing controller or driving unit can send programming data to each pixel based on the remapped information (or rearrange the read data of each pixel based on the remapped information).

[0125] Fig.15 A sequence of steps for remapping subpixels according to another embodiment of the present invention is shown. At step 1502, a group of defective micro-devices or pixels can be identified. At the next step 1504, the types of micro-devices can be remapped to reduce the effects of the defects. At the next step 1506, the connections connecting each micro-device to the corresponding pixel circuit based on the new mapping information can be rearranged / redesigned; and further at the next step 1508, the connections between the micro-devices and the pixel circuit based on the new arrangement can be implemented.

[0126] Fig.16 A schematic diagram of a microdevice with pixel circuits arranged according to another embodiment of the present invention is shown. Here, multiple microdevices 1602-1, 1602-2, and 1602-3 can be connected to their corresponding pixel circuits 1604 and data lines 1606. In one case, at least one microdevice / pixel (e.g., 1602-4) is not hardwired to a data (or signal) line. The type of such a microdevice can be changed based on defect information. Based on the mapping of the microdevice type (e.g., red, green, or blue) to the pixel (sub-pixel), the pixel is connected to the corresponding data line.

[0127] Fig.17 A schematic diagram of a micro-device with pixel circuits arranged according to another embodiment of the present invention is shown. In another case, more than one pixel (or sub-pixel), such as 1702-1, 1702-2, 1702-3, 1702-4, is not hard-wired to a data line (or signal line). Based on the micro-device mapping after defect analysis, the pixel (sub-pixel) can be connected to the corresponding data line (or signal line).

[0128] Fig.18A schematic diagram of a microdevice with pixel circuits arranged according to another embodiment of the present invention is shown. In another case, the pixel circuits (sub-pixels), such as 1804-1, 1804-2, and 1804-3, are not hardwired to the microdevice. After mapping the type of each microdevice based on defect analysis, the microdevice 1802 is connected to the pixel circuit accordingly. There may be more than one microdevice connected to the same circuit, or the microdevice is not connected to any pixel circuit.

[0129] Fig.19 A schematic diagram of a microdevice with pixel circuits arranged according to another embodiment of the present invention is shown. In one case, the microLED plane can have a bonding area 1908 corresponding to the bonding area of ​​the pixel circuits (sub-pixels) in the backplane. The microdevices 1902 are connected to the bonding area 1908 according to the type assigned to them after defect analysis. The bonding area can be a through hole for metallization between the microdevice plane and the backplane or a bonding filler (bump). In another case, the bonding area on the backplane can be adjusted according to the defect analysis.

[0130] According to one embodiment, a display system on a system substrate may be provided. The display system may include a pixel array, wherein each pixel includes a group of sub-pixels arranged in a matrix; the group of sub-pixels includes at least one defective sub-pixel; and a defect mapping block for mapping data from the at least one defective sub-pixel to at least one surrounding spare sub-pixel.

[0131] According to some embodiments, the brightness value of the defective sub-pixel can be shared among the surrounding spare sub-pixels based on a predefined value. A lookup table or formula can be used to extract the brightness share of the surrounding spare sub-pixels. The brightness value of the defective sub-pixel can be shared with one of the surrounding spare sub-pixels that is closest to the geometric distance of the defective sub-pixel. The brightness value of the defective sub-pixel can be shared equally among the surrounding spare sub-pixels.

[0132] According to another embodiment, a method for repairing a pixel circuit comprising multiple pixels may include: providing a group of more than two sub-pixels and a spare sub-pixel for each pixel; detecting at least one defective sub-pixel in the group of sub-pixels; and converting the spare sub-pixel using color conversion or a color filter to produce the same color as the defective sub-pixel.

[0133] According to some embodiments, the group of sub-pixels may include a red sub-pixel, a green sub-pixel and a blue sub-pixel. The spare sub-pixel may include a blue sub-pixel or a combination color sub-pixel.

[0134] In another embodiment, the method may further include: providing a color conversion material to convert the spare blue sub-pixel to the same primary color as the defective sub-pixel. The color conversion material is one of the following: quantum dots or phosphors. The color conversion material may cover the spare blue sub-pixel by one of the following methods: printing process, patterning process or stamping process.

[0135] In yet another aspect, the method may further include providing a color filter to convert the spare combined color sub-pixel to the same primary color as the defective sub-pixel.

[0136] Yet another embodiment provides a method of repairing a pixel circuit. The method may include: providing a pixel including more than one primary sub-pixel having a high wavelength emission (e.g., blue); applying a color conversion material to at least one of the primary sub-pixels to convert the high wavelength emission to an emission wavelength different from the high wavelength emission; identifying a defective sub-pixel in the primary sub-pixel; and mapping a spare sub-pixel to the same primary color as the defective primary sub-pixel by using the color conversion material.

[0137] According to yet another embodiment, a method of repairing a pixel circuit may be provided. The method may include: providing a pixel including more than one primary sub-pixel having a combined wavelength emission (e.g., white); applying a color filter material to at least one of the primary sub-pixels to convert the combined wavelength emission to a different emission wavelength; identifying a defective sub-pixel in the primary sub-pixel; and mapping a spare sub-pixel to the same primary color as the defective sub-pixel using the color filter material.

[0138] According to some embodiments, a method for repairing a pixel circuit may be provided. The method may include: providing a pixel including at least one high wavelength (e.g., blue) primary sub-pixel; providing at least one spare sub-pixel having the same wavelength; identifying defective sub-pixels in the primary sub-pixels and the spare sub-pixels; and mapping a color conversion layer to non-defective sub-pixels such that there is at least one sub-pixel for each expected primary sub-pixel.

[0139] According to another embodiment, a method for repairing a pixel circuit may be provided. The method may include: providing a pixel including at least one combined color sub-pixel (e.g., white); providing at least one spare sub-pixel having the same combined color; identifying defective sub-pixels in the primary pixel and the spare sub-pixels; and mapping the color filter layer to the non-defective sub-pixels so that there is at least one sub-pixel for each expected primary sub-pixel.

[0140] According to another embodiment, a method for replacing a defective sub-pixel with a spare sub-pixel in a display system may include: providing periodic spatial changes to the positions of sub-pixels in a display; calculating the maximum distance and the minimum distance between the spare sub-pixel and the defective sub-pixel; extracting the coordinate changes of the sub-pixel; and replacing the defective microdevice with the spare sub-pixel based on the calculated changes.

[0141] According to some embodiments, extracting the coordinate variation of a sub-pixel may include the following steps: calculating a maximum allowable spatial variation based on an acceptable spatial non-uniformity in a signal of the sub-pixel; calculating a number of spare sub-pixels based on a defect rate of the sub-pixel and the maximum allowable spatial non-uniformity; transferring the sub-pixels to a system substrate based on the calculated spatial variation; and allocating the spare sub-pixels among the sub-pixels in the system substrate based on the maximum allowable variation and the defect rate.

[0142] According to other embodiments, the method may further include: replacing the defective sub-pixel with a spare sub-pixel; calibrating the system based on the induced variation and the spare sub-pixel; and correcting the sub-pixel signal using the calibration data.

[0143] According to yet another embodiment, a method of correcting spatial non-uniformity of an array of optoelectronic devices is performed by blocking a portion of a signal generated or absorbed by an optoelectronic device based on the spatial non-uniformity in the array.

[0144] In another case, an opaque layer is deposited and patterned on top of the optoelectronic device, wherein the area of ​​the opaque layer is proportional to the spatial non-uniformity. The opaque layer is part of the contact layer of the optoelectronic device. The opaque layer can be part of the array electrode. In addition, the size of the optoelectronic device is modified according to the spatial non-uniformity.

[0145] Photoelectric solid-state array

[0146] The present disclosure also relates to a microdevice array display device, wherein the microdevice array can be bonded to a backplane in a reliable manner. The microdevices are fabricated on a microdevice substrate. The microdevice substrate can include micro light emitting diodes (LEDs), inorganic LEDs, organic LEDs, sensors, solid-state devices, integrated circuits, microelectromechanical systems (MEMS), and / or other electronic components.

[0147] Light emitting diodes (LEDs) and LED arrays can be classified as vertical solid-state devices. The microdevice can be a sensor, light emitting diode (LED), or any other solid-state device grown, deposited, or monolithically fabricated on a substrate. The substrate can be a native substrate for the device layers or a receptor substrate to which the device layers or solid-state devices are transferred.

[0148] The receptor substrate can be any substrate and can be rigid or flexible. The system substrate can be made of glass, silicon, plastic, or any other commonly used material. The system substrate can also have active electronic components such as but not limited to transistors, resistors, capacitors, or any other electronic components commonly used in system substrates. In some cases, the system substrate can be a substrate with rows and columns of electrical signals. The system substrate can be a backplane with circuits to derive a micro-LED device.

[0149] To improve pixelation or adjust the light output distribution, one or more of the bottom layers after separation from the donor substrate (or carrier substrate) are being patterned. The resolution of the patterned bottom layers is at least the same as the pixel resolution (however, it can be a higher resolution). The patterning can be done to completely isolate the layers or to leave some thin layers between the patterns. In both cases, a common electrode (or patterned electrode) can be used to connect to these layers.

[0150] Fig. 20A An embodiment is depicted that includes a donor substrate 2010 having a lateral functional structure that includes a bottom plane of a sheet-like conductive layer 2012, a functional layer such as a light-emitting quantum well 2014, and a top pixelated conductive layer 2016. Conductive layers 2012 and 2016 can be composed of doped semiconductor materials or other suitable types of conductive layers. Top conductive layer 2016 can include several different layers.

[0151] In one embodiment, Fig. 20B As shown, a current distribution layer 2018 is deposited on top of the conductive layer 2016. The current distribution layer 2018 can be patterned. In one embodiment, the patterning can be performed by lift-off. In another case, the patterning can be performed by photolithography. In an embodiment, a dielectric layer can be deposited and patterned first and then used as a hard mask for patterning the current distribution layer 2018. After the patterning of the current distribution layer 2018, the top conductive layer 2016 can also be patterned to form a pixel structure.

[0152] like Fig. 20C As shown, after patterning the current distribution layer 2018 and / or the conductive layer 2016 , a final dielectric layer 2020 may be deposited over and between the patterned conductive layer 2016 and the current distribution layer 2018 .

[0153] The dielectric layer 2020 may also be patterned to form an opening 2030, such as Fig.20D As shown, access to the patterned current distribution layer 2018 is provided. An additional planarization layer 2028 may also be provided to planarize the upper surface, such as Fig.20E shown.

[0154] like Fig.20EAs shown, a filler 2032 is deposited on top of the current distribution layer 2018 in each opening 2030. The development structure with the filler 2032 is bonded to the system substrate 2050 through the filler 2054, as shown in FIG. Fig.20F As shown. Filler 2054 in system substrate 2050 can be separated by dielectric layer 2056. Other layers 2052 such as circuits, planarization layers, conductive traces, etc. can be located between system substrate filler 2054 and system substrate 2050. The bonding of substrate system filler 2054 to filler 2032 can be accomplished by fusion, anodic, hot pressing, eutectic or adhesive bonding. One or more other layers can also be deposited between the system and lateral devices.

[0155] The above describes a case where the lateral functional structure is pixelated from the top layer. However, the pixelation of the lateral structure from the top layer can be performed in different ways.

[0156] To improve pixelation or adjust the light output distribution, one or more of the bottom layers after the donor substrate (or donor substrates) are being patterned. The resolution of the patterned bottom layers is at least the same as the pixel resolution (however, it can be a higher resolution). The patterning can be done to completely isolate the layers, or to leave some thin layers between the patterns. In both cases, a common electrode (or patterned electrode) can be used to connect to these layers.

[0157] like Figure 20G As shown, donor substrate 2010 can be removed from a lateral functional device, for example, from conductive layer 2012. Conductive layer 2012 can be thinned and / or partially or fully patterned. In this case, conductive layer 2012 is thinned.

[0158] In some embodiments, a reflective layer or black matrix may be deposited and patterned to cover the areas on the conductive layer 2012 between pixels. After this stage, other layers may be deposited and patterned depending on the function of the device. For example, a color conversion layer may be deposited to adjust the color of the light generated by the pixels in the lateral device and the system substrate 2050. One or more color filters may also be deposited before or / and after the color conversion layer. The dielectric layers in these devices, such as dielectric layer 2020, may be organic, such as polyamide, or inorganic, such as SiN, SiO2, Al2O3, etc. Deposition may be accomplished by different processes, such as plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), and other methods. Each layer may consist of one deposited material or different materials deposited separately or together. The bonding material may be deposited only as part of the filler 2032 of the donor substrate 2010 or the filler 2054 of the system substrate. Some annealing may also be performed on certain layers. For example, the current distribution layer 2018 may be annealed depending on the material. In one example, the current distribution layer 2018 can be annealed at 500° C. for 10 minutes. Annealing can also be performed after different steps.

[0159] like Fig. 20H As shown, the donor substrate 2010 can be removed from the lateral functional device and the conductive layer 2012 is fully patterned to form an isolated pattern of the bottom conductive layer 2012 .

[0160] Fig.21A A cross-sectional view of an integrated structure according to an embodiment of the present invention is shown, wherein the patterned bottom conductive layer has an ohmic contact. To connect to these layers, an ohmic contact and / or a common electrode (or patterned electrode) may be used.

[0161] In this case, a specific ohmic contact 2102 is required to properly connect to the patterned bottom conductive layer 2012. In one embodiment, the ohmic contact can be similar to a normal conductive layer. In one case, the ohmic contact is a transparent material. In another case, if the ohmic contact is opaque, the ohmic contact is patterned to provide a path for light output. The pattern can be inside the isolated patterned conductive layer 2012 or at the edge of the isolated patterned conductive layer 2012. The isolated patterned conductive layer 2012 can also have a 3D shape, such as the shape of a lens (a portion of a sphere) to control the direction of light output.

[0162] 21B shows a cross-sectional view of an integrated structure with ohmic contacts and a dielectric layer between patterned bottom electrodes in accordance with an embodiment of the present invention.

[0163] Figure 21B-1Ohmic contact 2102-1 is shown inside isolated patterned bottom conductive layer 2012. Dielectric layer 2104 may be deposited and patterned around isolated patterned bottom conductive layer 2012. The dielectric layer may also be deposited before ohmic contact 2102 is deposited.

[0164] Figure 21B-2 The case where the ohmic contact 2102-2 is at the edge of the isolated patterned bottom conductive layer 2012 is shown. In the case of an external ohmic contact layer, the same layer can be used as a common electrode. In another case, another layer can be deposited on the top layer.

[0165] Fig. 21C A cross-sectional view of an integrated structure covering a patterned bottom electrode with another electrode is shown in accordance with an embodiment of the present invention. A common electrode 2106 may be deposited on the patterned bottom conductive layer 2012 with an ohmic contact 2102 and a dielectric layer 2104 therebetween.

[0166] According to one embodiment, a method of manufacturing a pixelated structure may be provided. The method may include: providing a donor substrate including a plurality of pixelated micro-devices; bonding a selected set of pixelated micro-devices from the donor substrate to a system substrate; and patterning a bottom conductive layer of the pixelated micro-devices after separating the donor substrate from the system substrate.

[0167] According to another embodiment, patterning the bottom conductive layer may include at least one of the following: thinning the bottom conductive layer or making an isolation pattern of the bottom conductive layer; providing an ohmic contact to the isolation pattern of the bottom conductive layer. The ohmic contact is one of the following: a transparent material or an opaque material. In the case where the ohmic contact is opaque, the ohmic contact is patterned.

[0168] According to some other embodiments, providing the ohmic contact to the isolation pattern of the bottom conductive layer includes providing the ohmic contact inside the isolation pattern of the bottom conductive layer or / and providing the ohmic contact at the edge of the isolation pattern of the bottom conductive layer.

[0169] According to other embodiments, the method may further include providing a patterned dielectric layer between the isolated patterns of the bottom conductive layer and providing a common electrode on the patterned bottom conductive layer.

[0170] While specific embodiments and applications of the present invention have been illustrated and described, it should be understood that the invention is not limited to the precise construction and composition disclosed herein and that various modifications, changes and variations may be apparent from the foregoing description without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for manufacturing a pixelated structure, comprising: providing a donor substrate comprising a plurality of pixelated microdevices; bonding a selective set of said pixelated micro-devices from said donor substrate to a system substrate; and After separating the donor substrate from the system substrate, the bottom conductive layer of the pixelated microdevice is patterned. 2 . The method according to claim 1 , wherein patterning the bottom conductive layer comprises at least one of: thinning the bottom conductive layer or making an isolation pattern of the bottom conductive layer. 3 . The method of claim 1 , further comprising providing an ohmic contact to the isolation pattern of the bottom conductive layer. The method of claim 1 , wherein the ohmic contact is one of: a transparent material or an opaque material. The method of claim 1 , wherein the ohmic contact is patterned while being opaque. 6 . The method of claim 1 , wherein providing an ohmic contact to the isolation pattern of the bottom conductive layer comprises providing the ohmic contact inside the isolation pattern of the bottom conductive layer. 7 . The method of claim 1 , wherein providing an ohmic contact to a patterned bottom conductive layer comprises providing the ohmic contact at an edge of the isolation pattern of the bottom conductive layer.

8. The method of claim 1, further comprising providing a patterned dielectric layer between the isolation patterns of the bottom conductive layer.

9. The method of claim 1, further comprising providing a common electrode on the patterned bottom conductive layer.

Images